Field of the Invention
This invention relates to a process for the production of 11,11,12,12-tetracyano-9,10-anthraquinodimethane or its derivatives (hereinafter referred to simply as TCNAQ or its derivatives).
Several organic semiconductive materials or compounds such as 7,7,8,8-tetracyanoquinodimethane or derivatives thereof (hereinafter referred to as TCNQ or its derivatives) have been produced and utilized in various fields because of their excellent semiconductive properties. Preparation of TCNQ derivatives is described, for example, by D. S. Acker et al., J. Am. Chem. Soc., 84, 3370 (1962), by R. C. Wheland, J. Org. Chem. 40 (21), 3101 (1975) and in U.S. Pat. No. 3,115,506. For instance, TCNQ is prepared by a method in which diethyl succinosuccinate used as a starting material is first converted into 1,4-cyclo-hexanedione and then reacted with malonitrile. The synthesis of 1,4-cyclohexanedione is particularly described by J. R. Vincent et al., J. Org. Chem., 3, 603 (1939) and the subsequent reaction is described in the report of Acker et al. mentioned above. As will be apparently noted from the literature of Vincent et al., the conversion of diethyl succinosuccinate into 1,4-cyclohexanedione involves hydrolysis and decarbonization reactions of diethyl succinosuccinate, which require very severe temperature conditions of 195.degree. to 200.degree. C. This imposes a great burden on the preparation of TCNQ.
On the other hand, Wheland et al. describe a method of preparing TCNQ derivatives. In this method, benzene derivatives, p-xylene derivatives or terephthalic acid derivatives are used as a starting material and converted into p-xylenehalides, followed by a sequence of reaction steps to obtain TCNQ derivatives. This method is disadvantageous in that a number of reaction steps are required for the preparation of the TCNQ derivatives and that tetracyano intermediate compounds obtained during the course of the reactions are sparingly soluble in ordinary solvents because of their high polarity. Accordingly, a large quantity of a solvent is required in the final reaction stage of obtaining TCNQ derivatives.
Thus, the known pfocesses of producing TCNQ or its derivatives disadvantageously involve extremely severe reaction conditions or a number of steps, say, seven or eight reaction steps. This is extremely disadvantageous in view of the reaction time, reaction yield and energy or power consumption required for the promotion of the reactions.